Demo

Thoughts

My gut feeling is this effect looks a bit odd without the animation, but it's because the jarring 20px jump. However, there's definitely room for CSS transitions and animations, though aside from the status of the document, I can't see where it's up to on the W3C site...

As soon as there's support for CSS animations and transitions in Firefox as well as Safari, I'm going to start deferring JavaScript animation effects over to the CSS.